whats better k and n or genuine part air filter ?

[Dead Eye]

If you really wanted to make the most out of it for track days etc then I guess you could, but for every day use its not required. As many have said, the Fazer tends to run a bit lean rich as standard so having more air shouldn't be too issuesome unless there is TOO much.

Regardless, I haven't needed to re-jet and ive not experienced any problems since having fitted mine.


Edit: Thanks to Gnasher for pointing out my stupid mistake... My theory was correct, just used the wrong terminology